Hearing assistance devices, such as hearing aids, are used to assist patient's suffering hearing loss by transmitting amplified sounds to ear canals. In one example, a hearing aid is worn in and/or around a patient's ear. Hearing aids are intended to restore audibility to the hearing impaired by providing gain at frequencies at which the patient exhibits hearing loss. In order to obtain these benefits, hearing-impaired individuals must have residual hearing in the frequency regions where amplification occurs. In the presence of “dead regions”, where there is no residual hearing, or regions in which hearing loss exceeds the hearing aid's gain capabilities, amplification will not benefit the hearing-impaired individual.
Individuals with high-frequency dead regions cannot hear and indentify speech sounds with high-frequency components. Amplification in these regions will cause distortion and feedback. For these listeners, moving high-frequency information to lower frequencies could be a reasonable alternative to over amplification of the high frequencies. Frequency translation (FT) algorithms are designed to provide high-frequency information by lowering these frequencies to the lower regions. The motivation is to render audible sounds that cannot be made audible using gain alone.
There is a need in the art for improved threshold-based fitting using frequency translation for hearing assistance devices.